The present invention relates to techniques for attaching conductors to a circuit board. More particularly, the invention relates to methods and apparatus for improved attachment of a conductor to a circuit board, which advantageously reduces conductor breakage during use.
Circuit boards have long been employed in electronic equipments, e.g., computers. In a typical computer, for example, there may be one or more circuit boards on which a variety of digital and analog components may be mounted. One or more conductors may be employed to supply power, data, and the like to each circuit board. To facilitate discussion, FIG. 1 is a prior art illustration of a typical circuit board 100. Circuit board 100 may include any variety of analog and digital components, and may be employed as, for example, a power distribution board, a logic board, or the like.
Power and data may be supplied to circuit board 100 via any number of conductors. By way of example, there are shown in FIG. 1 conductors 102(a) and 102(b), which may be employed to supply for example +5 V and ground to circuit board 100. Electrical considerations may require conductors 102 to assume a variety of sizes and shapes, including flat bands. For good electrical conductivity, conductors 102(a) and 102(b) may be formed of a highly conductive metal such as copper, aluminum, an alloy thereof, or the like.
Conductors 102(a) and 102(b) may be inserted into apertures in the board, e.g., respective apertures 104(a) and 104(b), to permit conductors 102(a) and 102(b) to be subsequently soldered to circuit board 100. Soldering may be accomplished as circuit board 100, including conductors 102(a) and 102(b) disposed in apertures 104(a) and 104(b), is passed through a solder wave machine.
In some solder wave systems, for example, circuit board 100 may be passed over a pool of molten solder material, e.g., lead or an alloy thereof, to permit the molten solder material adhere to conductor leads and component leads which protruded out of the underside of the board. The adhered solder material, after solidifying, solders the leads of conductors and components to their respective apertures.
While the above technique adequately insures that conductors be securely soldered to its circuit board during manufacturing, it has been found that the heat of the soldering operation renders some conductors brittle near the solder point, e.g., near aperture 104 in the illustration of FIG. 1. This brittle portion renders the soldered conductor susceptible to breakage when the board is handled during use and the conductor is flexed, e.g., in the subsequent steps of the manufacturing process, during shipping, installation, or the like.
The conductor breakage problem is particularly acute for boards whose conductors are frequently flexed by plugging and unplugging, e.g., for maintenance and update of those boards themselves or of other boards to which the soldered conductors are attached. If the soldered conductors are attached to a power distribution board, for example, the soldered conductors may be expected to be plugged and unplugged numerous times during its lifetime as boards to which the soldered conductors are attached, e.g., other circuit boards in the system, are installed, removed, and/or reinstalled. As can be appreciated from the foregoing, conductor breakage may shorten the useful life of the board to which the conductor is soldered, necessitating expensive and time consuming repair and/or replacement.
In view of the foregoing, there are desired apparatus and methods for reducing breakage in soldered conductors, particularly those that may be frequently flexed during manufacturing, installation, and use.